Very slow shut down.

Recently, every time I shut down my computer, instead of taking a couple second to shut down it takes about a minute or two. So I watched the screen one time and very quickly I saw what I think read... ctfmon is not responding and needs to be shut down. I think it was the window that pops up when something doesnt respond and you can manually end it. It comes up for like a second and than the computer shuts down.
Aside from that, occasionally whenever I try to open folders and the "Thumbnail view" is on, a window pops up saying that Windows Explorer has encountered an error and needs to shut down.

I've searched my computer for viruses and used Ad-aware SE personal and they both found nothing. So does anyone know what else could be the problem?